mutual

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Directed and received by each toward the other; reciprocal.
• adjective Having the same relationship to each other.
• adjective Possessed in common.
• adjective Of, relating to, or in the form of mutual insurance.
• noun A mutual fund.

from The Century Dictionary.

• Based on the principle of mutuality in sharing both burdens and benefits: as, a mutual insurance company.
• Reciprocally given and received; pertaining alike or reciprocally to both sides; interchanged: as, mutual love; to entertain a mutual aversion.
• Equally relating to or affecting two or more together; common to two or more combined; depending on, proceeding from, or exhibiting a certain community of action; shared alike.
• Common: used in this sense loosely and improperly (but not infrequently, and by many writers of high rank), especially in the phrase a mutual friend.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Reciprocally acting or related; reciprocally receiving and giving; reciprocally given and received; reciprocal; interchanged
• adjective Possessed, experienced, or done by two or more persons or things at the same time; common; joint
• adjective agreement among a number of persons to insure each other against loss, as by fire, death, or accident.
• adjective one which does a business of insurance on the mutual principle, the policy holders sharing losses and profits pro rata.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Having the same relationship, each to each other.
• adjective Reciprocal.
• adjective Possessed in common.
• adjective Owned by the members.
• noun A mutual fund, etc.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective common to or shared by two or more parties
• adjective concerning each of two or more persons or things; especially given or done in return